Editing FN P90 (section)

==Design==
[[File:PS90 breakdown.jpg|thumb|left|upright=1.2|A disassembled PS90 carbine, showing the major component groups. The standard P90 disassembles into similar component groups: 1) trigger group, 2) barrel & upper receiver,  3) butt plate, 4) magazine, 5) bolt carrier, 6) frame / lower receiver]]

The P90 is a [[selective fire]], [[Blowback (arms)|straight blowback]]-operated weapon with a cyclic [[rate of fire]] of around 850–1,100 rounds per minute.<ref name="jones2009"/><ref name="fnhusap90">{{cite web |url=http://www.fnhusa.com/l/products/law-enforcement/tactical/p90-series |title=FNH USA Tactical Weapons&nbsp;– The P90 Series |year=2012 |publisher=[[FNH USA]] |access-date=August 31, 2012 |url-status=dead |archive-url=https://web.archive.org/web/20120913064157/http://www.fnhusa.com/l/products/law-enforcement/tactical/p90-series/ |archive-date=September 13, 2012 }}</ref> The weapon is chambered for FN's 5.7×28mm ammunition. Its unusual shape is based on extensive [[ergonomic]] research.<ref name="jones2009"/><ref name="miller2001"/> The weapon is grasped by means of a thumbhole in the frame that acts as a [[pistol grip]], as well as an oversized [[trigger guard]] that acts as a [[foregrip]] for the shooter's support hand.<ref name="marchington2004"/> The P90 fires from a [[closed bolt]] for maximum accuracy, and its design makes extensive use of [[polymers]] for reduced weight and cost.<ref name="dettyTL2008"/> Overall, the weapon is relatively lightweight, weighing {{convert|2.5|kg|lb|abbr=on}} empty, or {{convert|3|kg|lb|abbr=on}} with a loaded 50-round magazine.<ref name="miller2001"/><ref name="marchington2004"/>

The P90 is notable for being fully [[ambidextrous]]—it can be operated by [[Handedness|right]] or [[Left handed|left-handed]] shooters with equal ease, and without making any modifications to the weapon.<ref name="marchington2004"/> FN Herstal has described it as the "first fully ambidextrous individual automatic weapon."<ref name=":0">{{cite web |url=http://www.fnherstal.com/html/p_90.htm |title=P90® Submachine Gun, 5.7x28mm |year=2002 |publisher=[[FN Herstal]] |access-date=October 15, 2011 |archive-url=https://web.archive.org/web/20020214012140/http://www.fnherstal.com/html/p_90.htm |archive-date=2002-02-14}}</ref> The [[charging handle]], [[magazine release]] and backup [[iron sight]]s are symmetrically distributed on both sides of the weapon, and the firing selector is located directly at the foot of the trigger, where it can be operated from either side by the shooter's trigger finger or support hand thumb.<ref name="fnhusap90"/> When fired, the P90 [[Downward ejection|ejects spent cartridge casings downward]] through a chute located behind the grip, so spent cases are kept out of the shooter's [[line of sight]].<ref name="marchington2004"/>

[[File:FNP90MAG02.jpg|thumb|upright|The P90's unique [[magazine (firearms)|magazine]] has a capacity of 50 rounds, and it fits flush with the weapon's frame<ref name="dockery2007"/>|alt=]]
The P90 can be fitted with a [[Sling (firearms)|sling]] for greater ease of carry, and since the weapon has a fixed [[stock (firearms)|stock]] (as opposed to having a collapsing or [[folding stock]]), it can be quickly deployed when needed.<ref name="marchington2004"/><ref name="fnhp90">{{cite web |url=http://www.fnherstal.com/index.php?id=268&backPID=262&productID=63&pid_product=294&pidList=262&categorySelector=4&detail=&cHash=fb257c2c82 |title=Personal Defense Weapons: P90® Standard |year=2011 |publisher=[[FN Herstal]] |access-date=May 18, 2011 |archive-url=https://web.archive.org/web/20110317031144/http://www.fnherstal.com/index.php?id=268&backPID=262&productID=63&pid_product=294&pidList=262&categorySelector=4&detail=&cHash=fb257c2c82 |archive-date=March 17, 2011 |url-status=live }}</ref> The weapon's smooth, rounded contours prevent it from snagging on the shooter's clothing or equipment, and a small handstop at the weapon's front prevents the shooter's support hand from slipping in front of the [[Muzzle (firearms)|muzzle]] while firing.<ref name="miller2001"/><ref name="marchington2004"/> A hollow compartment inside the rear of the weapon's frame—accessed by removing the buttplate—allows for storage of a [[Firearm maintenance|cleaning kit]].<ref name="marchington2004"/>

The P90 was designed to have a length no greater than a man's shoulder width, to allow it to be easily carried and maneuvered in tight spaces, such as the inside of an [[Armoured fighting vehicle|armored vehicle]].<ref name="dockery2007"/> To achieve this, the weapon's design uses the unconventional [[bullpup]] configuration, in which the [[firearm action|action]] and magazine are located behind the trigger and alongside the shooter's face so that there is no wasted space in the [[Stock (firearms)|stock]].<ref name="dettyTL2008"/> The P90's dimensions are minimized by its unique horizontally mounted feeding system, wherein the [[Magazine (firearms)|box magazine]] sits parallel to the barrel on top of the weapon's frame.<ref name="dockery2007"/> The weapon overall has an extremely compact profile—it is the most compact fixed-stock submachine gun to be made.<ref name="dockery2007"/> The standard version of the weapon has an overall length of {{convert|500|mm|in|abbr=on}}, a height of {{convert|210|mm|in|abbr=on}}, and a width of {{convert|55|mm|in|abbr=on}}.<ref name="jones2009"/>

[[File:FN P90 Standard Submachine Gun Right Side.jpg|thumb|right|The P90 is fully ambidextrous]]
The P90 requires minimal [[Firearm maintenance|maintenance]], and it can be disassembled quickly and easily.<ref name="jones2009"/><ref name="wall2003"/> It is a modular firearm, consisting of four main component groups: the [[Gun barrel|barrel]] and optical sight group, the moving parts group, the frame and [[Trigger (firearms)|trigger]] group, and the [[Hammer (firearms)|hammer]] group. The P90's barrel is [[Forging|cold hammer-forged]] and [[Chrome plating|chrome-lined]], with an overall length of {{convert|263|mm|in|abbr=on}}.<ref name="fnhusap90"/> The barrel has eight [[rifling]] grooves with a right-hand [[twist rate]] of 1:231&nbsp;mm (1:9.1&nbsp;in), and it is equipped with a diagonally cut [[flash suppressor]] that also acts as a recoil compensator.<ref name="jones2009"/><ref name="fnhusap90"/> The stated service life of the barrel is 20,000 rounds.<ref name="dockery2007"/>

The P90 uses an internal hammer striking mechanism and a trigger mechanism with a three-position rotary dial fire control selector, located at the foot of the trigger. The dial has three settings: ''S''&nbsp;– safe, ''1''&nbsp;– semi-automatic fire, and ''A''&nbsp;– fully automatic fire. When set on ''A'', the P90's fire selector provides a two-stage trigger operation similar to that of the [[Steyr AUG]] assault rifle—pulling the trigger back slightly produces semi-automatic fire, and pulling the trigger fully to the rear produces fully automatic fire.<ref name="marchington2004"/>

===Ammunition===
{{main|FN 5.7×28mm}}
[[File:57lineup.jpg|thumb|Three of the small-caliber, high-[[muzzle velocity|velocity]] [[5.7×28mm]] cartridges as used in the P90. The left cartridge has a plain hollow tip, the center cartridge has a red [[Plastic-tipped bullet|plastic V-max tip]], and the right cartridge has a blue plastic V-max tip<ref name="dockery2007"/>]]
[[File:FNP90MAG01.JPG|thumb|The P90 magazine feed lips]]

Particularly significant to the design of the P90 is the small-caliber, high-velocity bottlenecked cartridge it uses. The 5.7×28mm cartridge was created by FN Herstal in response to a NATO requirement that called for a replacement for the 9×19mm Parabellum cartridge, which is commonly used in pistols and submachine guns.<ref name="oliver2007"/> The 5.7×28mm cartridge weighs 6.0&nbsp;g (93&nbsp;[[Grain (unit)|grains]])—roughly half as much as a typical 9×19mm cartridge—allowing the same number of rounds to be carried for less weight, or allowing more rounds to be carried for the same weight.<ref name="dettyTL2008"/><ref name="fnhusaammo2002">{{cite web |url=http://www.fnhusa.com/contents/tw_57x28system.htm |title=FNH USA, Inc. 5.7×28mm Weapon System |year=2002 |publisher=[[FNH USA]] |access-date=February 1, 2010 |archive-url=https://web.archive.org/web/20021225101159/http://www.fnhusa.com/contents/tw_57x28system.htm |archive-date=December 25, 2002}}</ref><ref name="fortierusg02">{{cite web |url=http://www.handgunsmag.com/ammunition/hg_militarytoday_200811 |title=Military Ammo Today |author=Fortier, David |year=2008 |publisher=Handguns Magazine |access-date=October 19, 2009 |archive-url=https://web.archive.org/web/20100122045316/http://www.handgunsmag.com/ammunition/hg_militarytoday_200811/ |archive-date=2010-01-22 |url-status=dead }}</ref> Since the 5.7×28mm cartridge has a relatively small diameter, an unusually high number of cartridges can be contained in a magazine.<ref name="amselle2011">{{cite web |url=http://www.tactical-life.com/online/special-weapons/fn-five-seven-57x28mm |title=FN FIVE-SEVEN 5.7×28mm |date=November 2011 |author=Amselle, Jorge |publisher=Special Weapons For Military & Police |access-date=November 9, 2011 |archive-url=https://web.archive.org/web/20111224172429/http://www.tactical-life.com/online/special-weapons/fn-five-seven-57x28mm/ |archive-date=December 24, 2011 |url-status=live }}</ref> The cartridge has a loud [[Muzzle blast|report]] and produces considerable [[muzzle blast#Muzzle flash|muzzle flash]] (when fired from a pistol), but it produces roughly 30&nbsp;percent less [[recoil]] than the 9×19mm cartridge, improving [[muzzle rise|controllability]].<ref name="fortierusg02"/> Due to its high velocity, the 5.7×28mm exhibits an exceptionally flat [[trajectory]], compared to typical pistol ammunition.<ref name="dockery2007"/><ref name="wall2003"/>

One of the design intents for the standard 5.7×28mm cartridge type, the ''SS190'', was that it has the ability to penetrate [[Kevlar]] [[ballistic vest|protective vests]] that stop conventional pistol bullets.<ref name="fortierusg02"/> Fired from the P90, the 5.7×28mm SS190 has a muzzle velocity of roughly 716&nbsp;m/s (2,350&nbsp;ft/s, Mach 2) and can penetrate the NATO [[CRISAT]] vest or a [[ballistic vest#Performance standards|Level IIIA]] Kevlar vest at a range of {{convert|200|m|yd|abbr=on}}.<ref name="wall2003"/><ref name="fortierusg02"/> FN states an effective range of {{convert|200|m|yd|abbr=on}} and a maximum range of {{convert|1,800|m|yd|abbr=on}} for the 5.7×28mm cartridge when fired from the P90.<ref name="jones2009"/>

In testing conducted by the [[Royal Canadian Mounted Police]] (RCMP) in 1999, the SS190 fired from the P90 at a distance of {{convert|25|m|yd|abbr=on}} exhibited an average penetration depth of {{convert|25|cm|in|abbr=on}} in [[ballistic gelatin]] covered with a Level II [[ballistic vest|vest]].<ref name="cutshaw2006">Cutshaw, Charlie (May 2006). "FN Herstal's Five-seveN Pistol". Tactical Response.</ref> The SS190 exhibited penetration depths ranging from {{convert|28|to|34|cm|in|round=0.5|abbr=on}} when fired from the P90 into bare ballistic gelatin, in tests conducted by [[Houston Police Department]] [[SWAT]].<ref name="wall2003"/> In testing, the SS190 and similar 5.7×28mm [[projectile]]s consistently turn base over point ("tumble") as they pass through ballistic gelatin and other media, using the {{convert|21.6|mm|in|abbr=on|adj=on}} projectile length<ref name="sterett2005">{{cite web |url=http://www.gunweek.com/2005/feature0110.html |title=FN 5.7mm Five-seveN Pistol Makes Civilian Model Debut |author=Sterett, Larry S. |publisher=Gun Week |year=2005 |access-date=October 19, 2009 |archive-url=https://web.archive.org/web/20121029110313/http://www.gunweek.com/2005/feature0110.html |archive-date=October 29, 2012 |url-status=dead |df=mdy-all }}</ref> to create a larger wound cavity.<ref name="miller2001"/><ref name="dettyTL2008"/><ref name="wall2003"/><ref name="bahde2009">{{cite web |url=http://www.tactical-life.com/online/combat-handguns/fnh-five-seven-odg-57x28mm |title=FNH Five-seveN ODG 5.7×28mm |author=Bahde, Dave |publisher=Combat Handguns |date=November 2009 |access-date=November 28, 2009 |archive-url=https://web.archive.org/web/20100717051637/http://www.tactical-life.com/online/combat-handguns/fnh-five-seven-odg-57x28mm/ |archive-date=July 17, 2010 |url-status=live }}</ref> However, some are skeptical of the bullet's [[ballistic trauma|terminal performance]], and it is a subject of debate among civilian shooters in the United States.<ref name="bahde2009"/>

The 5.7×28mm projectile potentially poses less risk of [[collateral damage]] than conventional pistol bullets, because the projectile design limits overpenetration, as well as the risk of [[ricochet]].<ref name="cutshaw2006"/><ref name="humphries2008"/> The lightweight projectile loses much of its [[kinetic energy]] after traveling only {{convert|400|m|yd|abbr=on}}, whereas a conventional pistol bullet such as the 9×19mm retains significant energy beyond {{convert|800|m|yd|abbr=on}}, posing greater risk of collateral damage in the event of a miss.<ref name="dockery2007"/> This range exceeds the engagement distances expected for the 5.7×28mm cartridge's intended applications, so the cartridge's limited energy at long range is not considered to be disadvantageous.<ref name="dockery2007"/> Since the SS190 projectile does not rely on fragmentation or the expansion of a [[hollow point bullet|hollow point]], the cartridge (and 5.7×28mm weapons) is considered suitable for military use under the [[Hague Convention of 1899]], which prohibits the use of [[expanding bullet]]s in [[warfare]].<ref name="bahde2009"/>

{| class="wikitable"
|+ Ballistic performance summary for various 5.7×28mm cartridges
|-
! Cartridge type
! SS195LF<ref name="fnhusacatalogammo08"/>
! SS197SR<ref name="fnhusacatalogammo08"/>
! EA Protector<ref name="gunblast"/>
! EA Varmintor<ref name="gunblast"/>
! EA S4<ref name="gunblast"/>
|-
! [[Projectile]] weight
| {{convert|1.8|g|gr|abbr=on}}
| {{convert|2.6|g|gr|abbr=on}}
| {{convert|2.6|g|gr|abbr=on}}
| {{convert|2.3|g|gr|abbr=on}}
| {{convert|1.8|g|gr|abbr=on}}
|-
! [[Muzzle velocity]]
| {{convert|777|m/s|abbr=on}}
| {{convert|640|m/s|abbr=on}}
| {{convert|716|m/s|abbr=on}}
| {{convert|747|m/s|abbr=on}}
| {{convert|930|m/s|abbr=on}}
|-
! [[Muzzle energy]]
| {{convert|550|J|abbr=on}}
| {{convert|530|J|abbr=on}}
| {{convert|665|J|abbr=on}}
| {{convert|650|J|abbr=on}}
| {{convert|785|J|abbr=on}}
|}

===Feeding===
The P90 uses a unique horizontally mounted feeding system—patented in the United States—that contributes to the weapon's compact profile and unusual appearance.<ref name="dockery2007"/> ''U.S. Patent 4,905,394'' ("Top mounted longitudinal magazine") was awarded in 1990, naming René Predazzer as the sole inventor.<ref>{{ cite web |url=http://patft.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PALL&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.htm&r=1&f=G&l=50&s1=4905394.PN.&OS=PN/4905394&RS=PN/4905394 |title=U.S. Patent 4,905,394 (Top mounted longitudinal magazine) |publisher=[[United States Patent and Trademark Office]] |access-date=July 15, 2010 |archive-url=https://web.archive.org/web/20151019115604/http://patft.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PALL&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.htm&r=1&f=G&l=50&s1=4905394.PN.&OS=PN%2F4905394&RS=PN%2F4905394 |archive-date=October 19, 2015 |url-status=live }}</ref> The [[Magazine (firearms)|detachable box magazine]] is mounted parallel to the P90's barrel, fitting flush with the top of the weapon's frame, and it contains 50 rounds of ammunition which lie in two rows facing left, offset 90° from the bore axis.<ref name="marchington2004"/> As the cartridges are pushed back by spring pressure and arrive at the rear end of the magazine, they are fed as a single row into a spiral feed ramp and rotated 90 degrees, aligning them with the [[Chamber (firearms)|chamber]].<ref name="marchington2004"/> The magazine body is composed of polymer, and it is translucent to allow the shooter to see the amount of ammunition remaining at any time.<ref name="marchington2004"/>

===Sights and accessories===
[[File:FN P90 Standard Muzzle End.jpg|thumb|right|P90 Standard with reflex sight and accessory rail]]
[[File:USGsight01.jpg|thumb|The normal and low-light reticles of the USG reflex sight used on the FN P90 / PS90 USG models. The ''USG'' [[reflex sight]] has a black T-shaped [[reticle]] with [[Tritium radioluminescence|tritium]] elements that glow red and are visible in dim lighting<ref name="rodriguez2008">{{cite web |url=http://www.shootingtimes.com/longgun_reviews/st_fnsfirepower_200811 |title=FN's Fun 5.7 Firepower |author=Rodriguez, Greg |year=2008 |publisher=Shooting Times |access-date=October 24, 2009 |archive-url=https://web.archive.org/web/20090429034133/http://www.shootingtimes.com/longgun_reviews/st_fnsfirepower_200811/ |archive-date=2009-04-29 |url-status=dead }}</ref>|alt=]]

The P90 was originally equipped with the Ring Sights HC-14-62 [[Reflector sight|reflex sight]], but the current weapon is instead fitted with the Ring Sights MC-10-80 sight, which was specifically designed for it.<ref name="gourley2003"/><ref name="ringsights01">{{cite web |url=http://www.ringsights.com/Products/sights/SightsDesc/MC-10-80.htm |title=Ring Sights MC-10-80 |publisher=Ring Sights |access-date=June 28, 2010 |archive-url=https://web.archive.org/web/20110715185206/http://www.ringsights.com/Products/sights/SightsDesc/MC-10-80.htm |archive-date=July 15, 2011 |url-status=live }}</ref> The HC-14-62 has a polymer housing and uses a forward-aimed [[fiber optic]] collector to illuminate the white daytime [[reticle]], which consists of a large circle of about 180 [[minutes of arc]] (MOA), with a 20 MOA circle surrounding a 3.5 MOA dot in the center. The MC-10-80 has an anodized aluminium housing, and has a similar black reticle. The night reticle for both the HC-14-62 and the MC-10-80 consists of an open ''T'' that is primarily illuminated by a [[Tritium illumination|tritium module]], and, in the HC-14-62, ambient light drawn in by an upward-facing collector. The sight is adjustable for both [[windage]] and [[Elevation (ballistics)|elevation]], and it can be used in conjunction with [[night vision equipment]].<ref name="ringsights01"/> As backup in case the reflex sight is damaged, a set of fixed iron sights is provided on each side of the reflex sight housing.<ref name="ringsights01"/> The newest MC-10-80, designated as the MC-10-80 Electronic, no longer uses tritium for its night reticle. Instead, the normal reticle can be illuminated in green powered by a [[CR2032]] [[Electric battery|battery]], with eight different [[brightness]] settings. The illuminated reticle makes the sight more versatile in a variety of different conditions.{{Citation needed|date=November 2021}}

The P90 has provisions for mounting a number of different types of accessories, including [[tactical light]]s and [[laser sights|laser aiming devices]]. A sling can be attached to the P90 for greater ease of carry, or it can be fitted with various [[sound suppressor]]s such as the Gemtech ''SP90'', which was designed specifically for the weapon in cooperation with FN Herstal.<ref name="jones2009"/> This [[stainless steel]] suppressor with a black oxide finish is built according to [[MIL-SPEC]]s, including [[saltwater]] [[corrosion resistance]].<ref name="jones2009"/> It has a length of {{convert|184|mm|in|abbr=on}}, a diameter of {{convert|35|mm|in|abbr=on}} and a weight of {{convert|680|g|lb|abbr=on}}.<ref name="jones2009"/> When [[speed of sound|subsonic]] ammunition is used in conjunction with the suppressor, it reduces the sound signature of the P90 by 33&nbsp;[[Decibel|dB]].<ref name="jones2009"/> A small case collector pouch for the P90 is available which fits over the ejection port and collects spent cases as they are ejected downward; the pouch will collect up to one hundred cases before filling.<ref name="gourley2003"/><ref name="wall2003"/>